4. More women than usual get pregnant during low-risk storms, but fewer women get pregnant during severe storms.

In 2007, researchers compared storm warnings and the number of babies born nine months later. The number of babies born rose nine months after a low-severity storm, but dropped nine months after people were preparing for a dangerous hurricane.

5. Parents are more likely to make more babies during storms than non-parents.

For couples who haven’t had kids yet, the storm won’t necessarily make them start conceiving. However, couples who are already parents are more likely to conceive when a storm hits, as long as the storm isn’t too severe.

9. So are blizzard babies.

After large 2010 storms, The Chicago Tribune asked local hospitals if they’d seen an increase in births. They said no. As a demographer explained, “Years of data must be gathered on either side of a single event to discern whether it was responsible for an elevated birth rate.”

10. But over a number of years, large and fatal disasters can cause people to have more children.

A 2005 study looked at birth rates in counties near the site of the Oklahoma City bombing in the 10 years following the attack. They found that birth rates were indeed higher close to the site, causing the researchers to conclude that “couples, confronted with stark evidence of life’s fragility, might have been motivated to reproduce to ensure that their genetic line would carry on.”

In other words, people may not have more sex during a dangerous event, but they might in the aftermath.